Jorge Ciccorossi
BR/SSD/SSC jorge.ciccorossi@itu.int
ITU-R World Radiocommunication Seminar - Geneva, 6-10 December 2010
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1) How to Identify Satellite Networks and other
Systems for which Coordination is Required ?
2) Several Interference Criteria utilized to evaluate compatibility between GSO satellite networks.
 Trigger Arc
 DT/T
 C/I
3) Possible methods to be used to facilitate coordination and sharing scenario between GSO.
4) How to optimize a filing to be submitted to ITU ?
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Appendix 5 indicates technical criteria utilized in every case, including:
•Regulatory provision containing form of coordination
•Sharing scenario associated to the case
•Frequency Band and Region
•Services
•Threshold/condition
•Calculation Method
See Table 5-1, Table 5-2 and Annex 1 to AP5
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Coordination between GSO/GSO under provision 9.7
 Criterion of Coordination Arc:
 To identify satellites with frequency overlap operating in the same direction inside the window of ± 8 to ± 10 , or ± 16 degrees from nominal orbital longitud, depending on the frequency band and service.
 Applicable to satellite networks in FSS (non plan)
BSS (non plan)
Meteorological-Satellite associated Space Operations in specific frequency bands ( see AP5 )
 Utilized by BR to identify coordination requirements.
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Coordination between GSO/GSO under provision 9.7
Coordination Arc is applied
Simple but Useful Exercise:
Approach Identifying Satellite Networks with which coordination may be required by using:
SNS-Online or SpaceQuery: SNS Online Link  http://www.itu.int/sns/query_builder.html
GSO Window=
20 E ± 10 degrees
Frequency
Band
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Coordination between GSO/GSO under provision 9.7
Result of Exercise of Coordination Arc Approach
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Coordination between GSO/GSO under provision 9.7
 Criterion of  T/T > 6 %
 Mask used by BR to establish coordination requirements in any other scenario where CA is not applicable.
 Utilized by Administrations to request BR to include or exclude networks in coordination process under No.9.41
 Described by Appendix 8 to RR.
 It measures the increase of Noise Temperature at Rx due to Interference as a generic method.
 It does not take into account: - wanted signal.
- interfering spectrum shape
 T/T > 6 % => Potential Harmful Interference
Further detailed analysis is needed to ensure that coordination is really needed ( e.g. C/I )
 T/T  6 % => No Harmful Interference
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
Interfering sat. network p’ g t
’
Ts p rs
Tx
ES p re
Wanted sat. network
AP8 describes the method including definitions
 T / T = ( p’ g t
’ g r
) / KLT
T e g r
Interfering power density level
 T (K)
T (K)
Transmission gain

:
 Valid for Simple Freq. Changing Transponders (Bent Pipe ) only
.
 Not applicable when satellite has on-board signal processing
(digital regenerating transponders, change of modulation, etc).
This case requires separate treatment of up and downlinks.

= p re
/ p rs
Power received at the earth stn.
Power received at the satellite
Rx
ES
Equivalent Satellite Link Noise Temperature:
T= Te +

Ts (K)
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
Separate treatment of Up and Downlink
(Wanted Satellite has on-board signal processing)
S’(Interfering)
Freq.Overlap in Downlink only p’ s
G`
3
L
D
S (Wanted)
 w
G
4
(
 w
)  T e
T e
S’(Interfering)
Freq.Overlap in Uplink only
G
2
S (Wanted)
 T s
T s
L u p’ e
 i
G
1
’(  i
)
 T / T=  T
E
/ T
E
 T / T = 10log( p’ s
) + G`
3
– L
D
+ G
4
(
 w
) – K – T
E
(dB)
 T / T =  T
S
/ T
S
 T / T = 10log( p’e) + G`1(  i) – LU + G2 – K –TS (dB)
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
.
Simple Freq.Changing Transponder (Bent Pipe)
S’(Interfering) Freq. Overlap Uplink Only
G
2
L
U p’ e
 i
G
1
’(  i
)
T e
T =T e
+  T s
S (Wanted)
S’ (Interfering) p’ s
G`
3
 T / T =
  T s
/T
 T / T = 10log

+ 10log( p’ e
) + G`
1
(
 i
) – L
U
+G2 – K – T (dB)
S (Wanted)
Freq. Overlap Downlink Only
L
D
 w
G
4
(  w
)
 T e
T e
T =T e
+  T s
T s
 T / T =  TE / T
 T / T = 10log( p’ s
) + G`
3
- L
D
+ G4 (

W
) - K
– T (dB)
 T s
T s
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
Simple Freq.Changing Transponder (Bent Pipe)
S’(Interfering)
Freq.Overlap in both links
G
2
S (Wanted)

T s
T s p’ e
 i
G
1
’(  i
) p’ s
G`
3
L
D
L
U
G
4
(  w
)
 w

T e
T e
T =T e
+  T s
 T/T= (  T e
+   T s
) / T
 T / T = ( p’ s g`
3 g
4 ( 
W
)
) / (k l
D
T) +  (p’ e g`
1
(  i
) g
2
) / (k l
U
T)
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 T/T Case II: Freq.Overlap in Opposite Direction of Tx.
(Inter-Satellite)
Downlink (interfering) overlaps Uplink(wanted)
S’(Interfering)
 s p’ s
G`
3
(
 s
)
Separate treatment of up & down links
L
S
G
2
(
 s
)
S (Wanted)

S
 T s
T s
S’(Interfering)
 T / T =  T
S
/ T
S
 T / T = 10log( p’ s
) + G`
3
(
 s
) - L s
+ G
2
(
 s
)
– K – T s
(dB)

S p’ s
Wanted Satellite has Simple Freq. Changing TXP (bent-pipe)
G`
3
( 
S
)
L
S
G
2
( 
S
)
T e
T =T e
+  T s
 T/T =
  T s
/ T
 T/T = 10log

+ 10log( p’ s
) + G`
3
(
 s
) - L s
+ G
2
(
 s
) -K -T (dB)

S
S (Wanted)
 T s
T s
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Coordination between GSO/GSO under provision 9.7
 C/I Criterion
 Utilized by BR to perform detailed examination of probability of harmful interference when so requested by Administrations under No.11.32A of RR.
 Based on methodology and protection criteria defined by
REC ITU-R S.741-2 and associated Rule of Procedure from RRB, or by common agreement between Adms.
 It takes into account: - Wanted signal
(level and type of carrier-modulation)
- Interfering signal
(level and spectrum shape)
- Overlapped BandWidth
 More accurate to perform inter-networks sharing analysis, based on quality and availability objectives.
 Used by operators in coordination meetings.
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Concept of C/I:
C/I = C/N + K
Protection ratio
( generally, between 12.2 – 14 dB, depending on the type of carriers )
Result of your Link Budget
( considering objectives like S/N or BER, availability, etc )
Protection required to ensure compatibility between networks
**C/I examination will be presented in detail in a separate document**
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Interference: Criteria and typical values
C
C/I C/N C/(N+I)
Degradation D (
C/(N+I))
I+N
“Delta” (dB)
N=KTB
D (
C/(N+I)) = 10log(1+i/n)
I
BW
I/N=-12 dB  Degradation @ 0.26 dB  ΔT/T = 6%
I/N=-10 dB 
I/N=- 6 dB 
0.4 dB
1 dB
For a single interference source.
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Multiple Interference Sources:


Worst case given by
I
Total
= 10.log [ 10 ( I1 / 10) + 10 ( I2 / 10) +…+ 10 ( In / 10) ] where I
Total
, I
1
, I
2
...I
n are in dBW.
In terms of C/I: c/i
Total
=
1
1 c/i
Adj. Sat .
1
+ + c/i
Terrest
1 c/i
Other
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 WRC’12 and other future conferences may modify the current criteria to establish coordination requirements, including the extension of CA to other bands and services (Resolution 901)
 Following aspects and combination of them are included in the proposals:
 Reduction of CA in certain portions of C and Ku bands
 Introduction of PFD Hard/Trigger Limits on Earth’s Surface and GSO
 Limitation of 9.41 under certain conditions of PFD outside CA
 Elimination of CA criterion => DT/T only for FSS C and Ku bands
 No Change
*Detailed Information of proposals and background of discussions may be found under Chapter 5/7/3 Draft CPM Report to WRC’12.
 SG4 and WP4A constantly consider updates to current interfering criteria, based on studies using latest technologies
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




Methods to facilitate coordination and sharing scenario between GSO


Frequency Separation
- Band Segmentation
- Channeling Plan
Polarization
Improvement of antenna system spatial discrimination
-Design of Antenna gain contours, roll-off and service areas associated to satellite beams
- Modifying antenna diameters in the ground segment
- Improvement to Earth Station Radiation Pattern
To Adjust orbital separation between adjacent satellites.
To Reorganize distribution of diferent types of carrier.
Use of advanced modulation/FEC technologies (eg. DVB-S2), signal coding and processing techniques (spread spectrum or CDMA, etc).
Re-engineering of the link budget, including modulation-FEC, power density levels, adjusting Quality and Availavibility Objectives in order to tolerate higher levels of interference.
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Satellite 1
Satellite 2
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Space Segment – Spatial Discrimination
-6.00
0.00
-2.00
-4.00
-10.00
-20.00
-1.20
-2.00
-1.20
-2.00
-6.00
-4.00
0.00
-10.00
-30.00
-20.00
-10.00
-4.00
-6.00
0.00
-4.00
-10.00
-2.00
-6.00
0.00
0.00
-20.00
-4.00
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Modifying Orbital Separation:
Exercise:
Assuming D/λ = 100 ; ES Antenna Paterns REC 465-5 / REC 580-6
Interference Reduction:
I f
- I i
= 25.log (φ i
/ φ f
) where φf: minimum final separation between satellites
φi: minimum initial separation between satellites
Scenario 1
Ө
1n
Ө
2n
Δ
Ө 1
= 2˚
= Δ
Ө 2
= ± 0.1˚
 Nominal Orbital Separation
 E-W Station Keeping
Interference Reduction with respect to Scenario 1
Scenario 2
Ө
1n
Ө
2n
Δ
Ө 1
= 3˚
= Δ
Ө 2
= ± 0.1˚ I f
- I i
= 25.log (1.8 / 2.8 ) = -4.8 dB
Warning: From Regulatory point of view, it may be an Impact of New Coordination
Requirements in some cases due to increase of interference to other satellites
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Ground Segment: Improving the Earth Station Radiation Pattern
Antenna Radiation Patterns Comparison
Sidelobes
50
10
0
-10
-20
40
30
20
40
30
20
10
60
50
0
-10
0.01
-20
AP8 REC-465-5
Gain (phi)
A - 25 LOG (phi) REC-580-6 ABCD log
0.1
1
Phi [deg]
10 100
BR / SSD / SNP 22

Changing the Earth Station Antenna Diameter:
Ga max [dBi]=
Gb max [dBi]=
Antenna A
G1 =
Phi m =
D/L =
Phi r =
Phi b=
Beamwidth=
Antenna B
G1 =
Phi m =
D/L =
Phi r =
Phi b=
Beamwidth=
43.2
56
35.21
0.35
259.28
0.56
47.86
0.27
23.34
1.50
59.40
1.68
47.86
1.17
60
50
40
30
20
10
0
0.01
-10
-20
Mainlobe and Near-Sidelobes
REC-580-6 Antenna Pattern
Gain (phi)
Antenna A Antenna B
0.1
1
REFERENCES - COMMENTS:
Antenna A= Typical 1.2M
Antenna B= Typical 13M
Phi [deg]
10 100
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Reorganizing distribution of different types of carrier
 To identify diferent types of carriers such as:
 TT&C


Analog TV/FM
Digital Data
 To consider their characteristics of diversity in terms of BW,
Max. Power and spectral density distribution.
 To group them in the frequency domain taking into account the distribution of similar carriers used by neighboring satellites.
 Off-axis eirp masks associated to type of carriers and frequency bands, as well as operational restrictions or relaxations, may be agreed during the coordination process.
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How to Optimize a Filing to be submitted to ITU ?
Goal ?
Favorable Findings
+ Realistic Info
To Ensure
Recording
+ Accuracy
MIFR
Positive Cycle for current & future networks
 Administrations are free to choose the way to organize a filing
 Coordination Request: -needs certain flexibility of parameters
-may be a General Approach
-specific
 Notification: -accurate parameters
-realistic
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Filing is Group Structured
Diversity of: Beam/Service Areas Frequencies Emissions Earth Stations
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Reorganize Filing considering diversity of frequency assignments and respective progress in coordination
For example: To split groups of frequency assignments by
-Beam/Service Areas
-Frequencies
-Emissions
-Earth Stations
Group 11  SA 1  Coord. Completed  Fav. Finding  MIFR
Group 12  SA 2  Coord. Not Completed  Further progress is required
( similar process )
( similar process )
Group 21  Typical 9m  Coord. Completed  Fav. Finding  MIFR
Group 22  Typical 1.2m
 Coord.Not Completed  Further progress is required
Remarks: locating worst cases in separated groups will ensure recording of successfully coordinated frequency assignments.
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*Text Document “ Frequency Sharing and Satellite Coordination between
GSO Networks. How to optimize a filing to be submitted to ITU ? “ complements this presentation providing further information and references.
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